The Ecobasic concept may not look like a Star Trek designer's view of future land transport, but it is the way Fiat believes small cars could evolve in the next few years. It is notable for extraordinary design features that include a dropped waistline at the rear door. Despite its blunt shape and short overall length of 3.48 m (11.4 ft), it has a remarkably good Cd figure of 0.28, it has a mass of only 750 kg (1650 lb), and it has been designed to achieve 160 km/h (100 mph) and attain an average fuel consumption of 3.0 L/100 km. It is powered by a 1.2-L multipoint direct-injection diesel engine and "robotized" gearbox. A further target is that the Ecobasic should sell for less than $5000.
Usually, when companies design such concepts that are far from production-ready, they are seen at international motor shows and then disappear from public view either to be developed or quietly forgotten. Seldom are they put at the disposal of specialist media for assessment; but that is what Fiat decided to do with the Ecobasic, inviting a small number of international journalists, including me (AEI European Editor) to drive the car. Allowances must be made when judging a concept vehicle for the fact that it is in a semi-raw state, that some elements may never make it to production, and that others need extensive development. But overall, it is possible to make general technical and aesthetic judgments. These judgments may help a manufacturer toward the decision to manufacture. This is particularly the case when the vehicle is highly unusual in form and features.
The Ecobasic is not a dream car but a model created through the combined efforts of Fiat's research and development staff with the intention of pushing back the boundaries of style, design, and construction, according to Fiat. Fiat demonstrated its ability to take very bold decisions with regard to off-beat designs when it decided to produce the Multipla, a vehicle that potential customers either loved or loathed; the Ecobasic follows on that refreshing approach but incorporates far more new technology - another reason why Fiat is showing caution. The company says it is a pilot project that embodies a number of new solutions, adding that some will be seen on standard production models within a short time; others will take longer to appear. But Fiat is cautious about saying whether or not the Ecobasic or something very much like it will be produced.
One of the central criteria for the design was that, despite its technology, it should be easy to drive. On Fiat's test track, the concept vehicle demonstrated that it is. Entry and egress are easy. The car has four seats that have steel tube frames described by Fiat designer Roberto Giolito, who was also involved with the Multipla. "The tubes are of different thicknesses," he said. "We used sophisticated technology to bend the tubing and distribute the load correctly. The design is the result of advanced study, and is an example of what may be done. At present, our suppliers are not ready for such technology." The seats can be fitted with an elasticized mesh.
The interior is minimalist, but with plenty of attractive design of functional items. The plain and simple dashboard is a flexible tubular structure containing light, repositionable storage compartments and is dominated by a huge, motorcycle-like speedometer. The instruments and controls, including sequential gearshift, are located on and around a cylindrical structure that looks as if it might have come from some form of industrial vacuum cleaner, its upper section incorporating a ventilation grille instead of using separate vents.
The little 45-kW (61-hp) diesel engine gives the car 0-100 km/h (0-62 mph) potential in 13 s. Fiat has elected to use a robotized Selespeed gearbox similar to that used by Alfa Romeo, which can be used as a normal automatic or changed sequentially. Fiat underlines that the key to its success lies with the development of advanced software that is able to integrate engine control strategies with automatic transmission control strategies at a deep-seated level. The software coordinates the actions of both by simultaneous selection of the gear to be engaged and the engine service point (based on rpm and load). This makes for an easy-to-use system. Like most robotized manuals, it takes a while for the driver to become used to "playing" throttle and shift movements for real smoothness. Hustled quickly through a fairly tight radius turn on the Fiat test track, the Ecobasic showed marked understeer, but again the company stressed that the suspension, which it does not detail, is in its developmental phase.
The Ecobasic is a two-box design. Its bodyshell tapers noticeably towards the rear, contributing to its very good Cd, although the windshield is surprisingly upright for such an aerodynamic car. The beltline drops to allow very deep rear passenger side windows, which swivel outward. The car could have either four or three (two front, one rear) passenger doors; deleting the fourth is logical as normally it is only the sidewalk-side rear door that is opened. The car does not have an opening hood; instead it has an access panel similar to that fitted to Audi's new aluminum A2. The panel allows windshield washer and radiator fluids plus engine oil level to be checked and topped. It also has a facility for battery charging. The Ecobasic has a tailgate, and airflow control at its rear includes a system to avoid drag-inducing vortices. The car's tapering shape accentuates the rear-wheel arches, and its underside is aerodynamically clean. The thermally efficient diesel engine needs to dissipate relatively little heat, so only a small air intake is fitted to the car.
The 16-valve 1.2-L diesel engine uses a development of the JTD high-pressure direct-injection system, which Fiat pioneered and Bosch developed for production. The Ecobasic's second-generation system is based on multiple-injection technology, or Multijet, which will soon be offered on production cars. (Demonstrated on a pre-production Punto, it offers very good performance and low noise levels.) Emissions are said to be 30-40% less and performance 6-7% better. The key to the engine's performance lies in the control unit that opens and closes the injectors electronicallyÑand in the injectors themselves. A primary facilitator is the electronic control unit; its capacity is greater than units currently on the market because it can conduct a series of injections very close to one another. Multiple injections ensure more precise control of temperatures and pressures within the combustion chamber and more efficient use of air taken into the cylinders.
Current production common-rail diesel engines routinely use a pre-injection sequence to raise temperature and pressure inside the cylinder, which facilitates smoother, quieter, and quicker combustion when the main injection is made. Dividing that main injection into several parts brings added improvements, including lower noise, reduced emissions, and increased performance. Fiat researchers mapped the multiple, variable injection sequences for optimization under various load conditions.
This approach allows improvements such as greater torque, less noise, and/or improved emissions. For the little Ecobasic Fiat, which is very much a city car concept, it focused on reducing emissions and increasing torque at low engine speeds. The robotized gearbox complements these gains by making the most of the available torque. Its software integrates engine and automatic gearbox electronic control unit (ECU) strategies at a fundamental level, according to Fiat. Fuel savings of up to 10% on a combined cycle and 20% for the urban cycle have been achieved.
Of course, the effect of such technology would be degraded if the Ecobasic were a heavy vehicle for its size. At 750 kg (1650 lb), it is not. To achieve this figure, Fiat mixes steel and plastic. The car has a pressed sheet steel spaceframe suitable for cladding with plastic body parts that have different properties according to their purpose. Mass-dyed thermoplastics, with the same color throughout their thickness, are used for fenders and nonload-bearing panels. Easily replaceable, they can withstand minor damage and scratching. Low-weight thermoset material is used for hood, door frames, and roof. A polycarbonate rear windshield is co-molded into the tailgate using "an innovative process," reports Fiat. For the first time on a Fiat car, the front end is pre-assembled and inspected outside the factory by Magneti Marelli and screwed to the front body struts. The bumpers are supported by a deformable safety beam and coated in polypropylene.
Stuart Birch
AEI October 2000
